Those brown/red gases are different Nitrogen oxides and very unhealthy to breath in. I had to do this once and the fume hood was barely keeping up. It filled quick with the stuff. Later, we had to get the copper back and were deducted points for each fraction of a gram lost.

Once I discovered a large hole with black edges on the back of my lab coat. Someone must have spilled sulfuric acid on it without noticing. So it makes sense to wear them in a crowded lab, even if you think you yourself don’t need to.